chore: snapshot production code before Apple Design UI refinement

go/vehicle-gateway/cmd/legacy-mileage-migrate/main_test.go

@@ -1,7 +1,9 @@
 package main
 
 import (
+	"context"
 	"database/sql"
+	"strings"
 	"testing"
 )
 
@@ -54,3 +56,10 @@ func TestNullableTotalMileageConvertsMetersToKM(t *testing.T) {
 		t.Fatalf("invalid mileage should remain nil, got %#v", got)
 	}
 }
+
+func TestApplyRejectsUnknownProtocolBeforeDatabaseAccess(t *testing.T) {
+	err := applyMigration(context.Background(), nil)
+	if err == nil || !strings.Contains(err.Error(), "no verified protocol") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}